The fallout from George Osborne's attempt to link ex-Labour ministers to the Libor-rigging scandal continues, with Baroness Shriti Vadera securing a retraction from the BBC after the claims were repeated on last week's Question Time.

Labour's former City envoy instructed lawyers to pursue libel complaints against broadcasters and newspapers after a since-retracted comment by the columnist Dominic Lawson on Question Time on 5 July.

Lawson, who appeared on the show alongside Tory MP Louise Mensch and former Sex Pistols frontman John Lydon, claimed that Osborne had said Vadera and former Labour government ministers pressured Barclays to push down its Libor rate so the bank would appear more solvent than it actually was.

Vadera has strenuously denied the allegation, which was retracted by the Independent columnist shortly after his appearance on David Dimbleby's BBC1 current affairs show.

Amber Melville-Brown, the lawyer acting on behalf of Vadera, said in a statement: "Dominic Lawson swiftly retracted the allegation and this retraction has been published on the BBC Question Time website. The relevant section is being removed by the BBC from the iPlayer clip of the programme. The BBC has also offered our client a letter expressing its regret at any embarrassment caused to her."

"Our client did not discuss with anyone in any form of communication at any point the fixing or manipulation of Libor and was unaware of any attempts by banks to manipulate Libor."

Tucker told MPs on the Commons Treasury select committee he had not been pressured by Vadera, then City minister Ed Balls or ex-No 10 chief of staff Jeremy Heywood. He said: "I don't think I spoke to Shriti Vadera throughout this whole period."

Unlike other BBC current affairs shows, Question Time is not broadcast live. The show is filmed shortly before it is broadcast at 10.35pm on Thursday evenings.

Lawson said in a statement after last week's show: "On BBC Question Time on Thursday 5 July I said that George Osborne had alleged that Shriti Vadera was involved in attempts to influence Barclays bank on Libor. Baroness Vadera has in fact denied any involvement at all in this matter and I am happy to acknowledge that George Osborne did not make this allegation."

Lawyers for Vadera are also understood to have written to other media outlets requesting that they contact them before writing about the ex-minister. The allegations have become a prominent subplot in the scandal that forced the resignation of the Barclays chief executive Bob Diamond last week.

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